2. Measurement Process Characterization
2.4. Gauge R & R studies

2.4.3.

Data collection for time-related sources of variability

Time-related analysis

The purpose of this page is to present several options for collecting data for estimating time-dependent effects in a measurement process.

Time intervals

The following levels of time-dependent errors are considered in this section based on the characteristics of many measurement systems and should be adapted to a specific measurement situation as needed.

1. Level-1 Measurements taken over a short time to capture the precision of the gauge

2. Level-2 Measurements taken over days (of other appropriate time increment)

3. Level-3 Measurements taken over runs separated by months

Time intervals

• Simple design for 2 levels of random error
• Nested design for 2 levels of random error
• Nested design for 3 levels of random error

In all cases, data collection and analysis are straightforward, and there is no reason to estimate interaction terms when dealing with time-dependent errors. Two levels should be sufficient for characterizing most measurement systems. Three levels are recommended for measurement systems where sources of error are not well understood and have not previously been studied.